From patchwork Fri Oct 28 08:52:06 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 688292 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3t4yHy0dxdz9t0p for ; Fri, 28 Oct 2016 19:54:54 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935654AbcJ1Iyx (ORCPT ); Fri, 28 Oct 2016 04:54:53 -0400 Received: from mailout1.hostsharing.net ([83.223.95.204]:57925 "EHLO mailout1.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937911AbcJ1Iyw (ORCPT ); Fri, 28 Oct 2016 04:54:52 -0400 Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout1.hostsharing.net (Postfix) with ESMTPS id ADC62101B21F0; Fri, 28 Oct 2016 10:54:50 +0200 (CEST) Received: from localhost (3-38-90-81.adsl.cmo.de [81.90.38.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 59548600BBDA; Fri, 28 Oct 2016 10:54:49 +0200 (CEST) X-Mailbox-Line: From cc74b62ca37389d863aeae1573208a2be240b837 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Lukas Wunner Date: Fri, 28 Oct 2016 10:52:06 +0200 Subject: [PATCH v2 7/9] ACPI / hotplug / PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit To: linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Bjorn Helgaas Cc: Mika Westerberg , "Rafael J. Wysocki" , Andreas Noever , Keith Busch Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org We cache the PCI_EXP_SLTCAP_HPC bit in pci_dev->is_hotplug_bridge on device probe, so there's no need to read it again when adding the ACPI hotplug context. Here's the call chain to prove that no ordering issue is introduced: pci_scan_child_bus [drivers/pci/probe.c] pci_scan_slot pci_scan_single_device pci_scan_device pci_setup_device set_pcie_hotplug_bridge [is_hotplug_bridge bit is set here] pci_scan_bridge pci_add_new_bus pci_alloc_child_bus pcibios_add_bus [arch/(x86|arm64|ia64)/...] acpi_pci_add_bus [drivers/pci/pci-acpi.c] acpiphp_enumerate_slots [drivers/pci/hotplug/acpiphp_glue.c] acpiphp_add_context device_is_managed_by_native_pciehp [is_hotplug_bridge bit is queried here] No functional change intended. Tested-by: Mika Westerberg Reviewed-by: Rafael J. Wysocki Signed-off-by: Lukas Wunner --- drivers/pci/hotplug/acpiphp_glue.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index a46b585..b286a56 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -225,14 +225,11 @@ static void acpiphp_post_dock_fixup(struct acpi_device *adev) /* Check whether the PCI device is managed by native PCIe hotplug driver */ static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev) { - u32 reg32; acpi_handle tmp; struct acpi_pci_root *root; /* Check whether the PCIe port supports native PCIe hotplug */ - if (pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, ®32)) - return false; - if (!(reg32 & PCI_EXP_SLTCAP_HPC)) + if (!pdev->is_hotplug_bridge) return false; /*